<!DOCTYPE html>
<html>
<head>
<link rel="help" href="http://www.w3.org/TR/DOM-Level-3-Events/#events-WheelEvent">
<script src="../../../resources/testharness.js"></script>
<script src="../../../resources/testharnessreport.js"></script>
<script src="../../../resources/gesture-util.js"></script>
<script src="../../../virtual/percent-based-scrolling/resources/percent-based-util.js"></script>
</head>
<body>
<span id="parent">
  <div id="target" style="border:solid 1px green; width:220px; height:70px; overflow:scroll; white-space:nowrap;">
    TOP TOP TOP TOP TOP TOP TOP TOP TOP TOP TOP TOP TOP TOP<br/>
    Scroll mouse wheel over here<br/>
    Scroll mouse wheel over here<br/>
    Scroll mouse wheel over here<br/>
    Scroll mouse wheel over here<br/>
    Scroll mouse wheel over here<br/>
    Scroll mouse wheel over here<br/>
    END END END END END END END END END END END END END END<br/>
  </div>
</span>
<div id="console"></div>
</body>
<script>
var deltaX = 0;
var deltaY = 0;

promise_test(async () => {
  // Basic checks.
  assert_equals(WheelEvent.__proto__, MouseEvent);
  assert_equals(WheelEvent.prototype.__proto__, MouseEvent.prototype);
  assert_equals(WheelEvent.DOM_DELTA_PIXEL, 0x00);
  assert_equals(WheelEvent.DOM_DELTA_LINE, 0x01);
  assert_equals(WheelEvent.DOM_DELTA_PAGE, 0x02);

  var testDiv = document.getElementById('target');
  assert_equals(window.onwheel, null);
  assert_equals(document.onwheel, null);
  assert_equals(testDiv.onwheel, null);
  testDiv.addEventListener('wheel', wheelHandler);
  var x = testDiv.offsetLeft + 5;
  var y = testDiv.offsetTop + 5;
  await mouseMoveTo(x, y);
  const pixelsToScroll = 40;
  await smoothScroll(
    pixelsToScroll, x, y, GestureSourceType.MOUSE_INPUT, 'downright', SPEED_INSTANT
  );

  if (isPercentBasedScrollingEnabled()) {
    await waitForAnimationEndTimeBased(() => { return testDiv.scrollTop; });
    await waitForAnimationEndTimeBased(() => { return testDiv.scrollLeft; });

    const {
      x: expectedScrollLeft,
      y: expectedScrollTop,
    } = calculateExpectedScroll(testDiv, pixelsToScroll, pixelsToScroll);

    // Windows and Linux values appear to be slightly different
    assert_approx_equals(testDiv.scrollTop, expectedScrollTop, 0.05);
    assert_approx_equals(testDiv.scrollLeft, expectedScrollLeft, 0.1);
  } else {
    await waitFor( () => {
      return deltaX > 0 && deltaY > 0 && deltaX == testDiv.scrollLeft &&
          deltaY == testDiv.scrollTop;
    });
  }
}, "Tests the basic functionality of the standard wheel event");

var testEvent;
function wheelHandler(e) {
  testEvent = e;
  assert_equals(testEvent.__proto__, WheelEvent.prototype);
  assert_equals(testEvent.__proto__.__proto__, MouseEvent.prototype);
  if (e.deltaX)
    deltaX = e.deltaX;
  if (e.deltaY)
    deltaY = e.deltaY;
  assert_equals(testEvent.deltaZ, 0);
  assert_equals(testEvent.deltaMode, WheelEvent.DOM_DELTA_PIXEL);
}
</script>
</html>
